@muameen this will require taking apart the area around the radio and messing with wires.
As a quick, cheap workaround, I suggest a FM transmitter. Such as this one
https://www.amazon.com/VicTsing-Bluetooth-Transmitter-Wireless-Adapter/dp/B01DDPUQTS/ref=sr_1_1?ie=UTF8&qid=1498623219&sr=8-1-spons&keywords=fm+transmitter&psc=1
What this device does is connect to your music player via bluetooth or aux cable. Then it takes the sound and sends it to your car via FM radio. You would find a FM station that has no signal, and then tune the FM transmitter to transmit to this station. It can also charge your phone at the same time.